Abstract A chiral binaphthalene is bridged at the 2,2′-positions with methylene (CH2), ethylene (C2H4), propylene (C3H6) and butylene (C4H8) linkers, with the aim to vary the binaphthalene dihedral angle and hence to study the influence of the latter on the polybinaphthalene gas separation membrane performances. It was hypothesized that different angles would induce different membrane performances. The polymer membranes with the four different linkers show average gas selectivities, CO2/CH4 = 22 ± 3 and CO2/N2 = 28 ± 2, which strongly indicates that these polymers have strongly similar macromolecular structures. This is confirmed by CD spectroscopy which reveals the same Cotton effect patterns. The similarity in the macromolecular structures can be ascribed to a smaller than anticipated change in the dihedral angle introduced by the linkers, 4° of difference between ethylene, propylene and butylene, as demonstrated by DFT calculations.

中文翻译：

---

聚联萘分子结构对膜分离性能的影响

摘要 手性联萘在 2,2'-位与亚甲基 (CH2)、亚乙基 (C2H4)、亚丙基 (C3H6) 和丁烯 (C4H8) 连接，旨在改变联萘二面角，从而研究后者对聚联萘气体分离膜性能的影响。假设不同的角度会导致不同的膜性能。具有四种不同接头的聚合物膜显示出平均气体选择性，CO2/CH4 = 22 ± 3 和 CO2/N2 = 28 ± 2，这有力地表明这些聚合物具有非常相似的大分子结构。CD 光谱证实了这一点，该光谱揭示了相同的棉花效应模式。大分子结构的相似性可归因于接头引入的二面角变化小于预期，